Growth Performance and Immunity of Broilers Fed Sorghum-Soybean Meal Diets Supplemented with Phytases and Β-Mannanases.

Most grains and vegetable feedstuffs used in commercial poultry feed contain phytates and polysaccharides-non-starchy chemical structures that are not degraded by digestive tract enzymes. Exogenous enzymes optimize the use of dietary ingredients. This study aimed to determine whether combining ß-mannanases (400 g/ton) and phytases in broiler sorghum-soybean diets could improve performance and immunity in broilers. Four diets were randomized in a 2 × 2 factorial design, with two phytase levels (500 or 1500 FTU/kg) and ß-mannanase supplementation (0-400 g/ton; 158 million units/kg minimum enzyme activity). Six replicate battery cages of 10 chicks were fed each diet ad libitum. To assess cellular and humoral immune responses, 10 birds per treatment were euthanized on day 21. Supplementation with ß-mannanase enzymes led to increased body weight and a higher feed conversion index (FCI) (p < 0.05). The phytase factor improved the FCI at 1500 FTU/kg (p < 0.05). Supplementation with ß-mannanases improved the immune response by increasing the IgA concentration in the duodenum (95%) and total serum immunoglobulins (p < 0.05). The morphometric index increased in all organs (p < 0.05), and the heterophile/lymphocyte ratio (HLR) decreased by 50% (p < 0.05). Supplementing broilers with ß-mannanases in sorghum-soybean meal diets with phytases improved their performance and immunity.

Mycobacterium bovis naturally infected calves present a higher bacterial load and proinflammatory response than adult cattle.

Granulomas are characteristic bovine tuberculosis lesions; studying this structure has improved our understanding of tuberculosis pathogenesis. However, the immune response that develops in granulomas of young cattle naturally infected with Mycobacterium bovis (M. bovis) has not been fully studied. Our previous work described an atypical pattern in granulomatous lesions of cattle younger than 4 months (calves) naturally infected previously M. bovis that did not correspond to the histological classification previously proposed. Histologically, granulomas from calves lack a connective tissue capsule and have fewer multinucleated giant cells (MGCs) and more acid-fast bacilli (AFB) than the classic tuberculosis lesions found in cattle older than 1 year (adults); this suggests a deficient immune response against M. bovis infection in young animals. Therefore, we used IHC and digital pathology analysis to characterize the in situ immune response of granulomas from young and adult cattle. The immunolabeling quantification showed that granulomas from calves had more mycobacteria, CD3+ cells, IFN-γ, TNF-α, and inducible nitric oxide synthase (iNOS) than those of adult cattle. Furthermore, calf granulomas showed lower immunolabeling of MAC387+, CD79+, and WC1+ cells without connective tissue surrounding the lesion and were associated with less vimentin, Alpha Smooth Muscle Actin (α-SMA), and TGF-ß compared with granulomas from adult cattle. Our results suggest that the immune responses in granulomas of cattle naturally infected with M. bovis may be age dependent. This implies that an exacerbated proinflammatory response may be associated with active tuberculosis, producing more necrosis and a lower microbicidal capacity in the granulomas of calves naturally infected with M. bovis.

Ocular tuberculosis in a calf.

BACKGROUND: Bovine tuberculosis is a chronic inflammatory disease that causes granuloma formation mainly in retropharyngeal, tracheobronchial, mediastinal lymph nodes and lungs of bovines. The presence of these lesions in other tissues such as the eyeball is very rare and difficult to diagnose. This study describes macroscopic and microscopic pathological findings in a calf with ocular and meningeal tuberculosis. CASE PRESENTATION: March 2019, an eight-month-old Holstein Friesian calf was identified in a dairy farm located in central Mexico with a clinical cough, anorexia, incoordination, corneal opacity and vision loss. At necropsy, pneumonia, lymphadenitis, meningitis, and granulomatous iridocyclitis were observed. The histopathological examination revealed granulomatous lesions in lung tissue, lymph nodes, meninges and eyes with the presence of acid-fast bacilli associated with Mycobacterium spp. CONCLUSION: To the best of our knowledge, this is the first report that describes macroscopic and microscopic pathological findings of ocular tuberculosis in cattle. This report highlights the importance of considering bovine tuberculosis in the differential diagnosis of corneal opacity and loss of vision in cattle.

Clinical evaluation, serological response and lesions generated by the A/Mexico/La Gloria-3/2009/H1N1 and A/swine/New Jersey/11/1976/H1N1 influenza viruses in colostrated and non-colostrated pigs.

Influenza A viruses cause respiratory disease in piglets, and maternal immunity plays an important role in protecting against Influenza virus infection. Nevertheless, in the presence of high levels of maternal antibodies against influenza, an adequate immune response is not developed. In this study, the effect of maternal antibodies against the swine influenza A/swine/New Jersey/11/1976/H1N1 virus (swH1N1) on clinical presentation, serological response, and lesions produced in colostrated and non-colostrated pigs was evaluated in pigs infected with the human influenza A/Mexico/La Gloria-3/2009/ H1N1 (pH1N1) and swH1N1 viruses. Our results indicated that between 2 and 4 days post-challenge, sneezing and mild nasal discharge were observed in all pigs. Body temperature in pigs from all treatment groups ranged between 39.2 and 39.3 °C. Pigs inoculated with the pH1N1 virus (421 g) exhibited a significantly lower daily weight gain than those inoculated with the swH1N1 virus (524 g). HI antibody titers against the pH1N1 virus were significantly different between colostrated (1.62) and non-colostrated (0.43) pigs. Significant differences in antibody titers were detected between pigs inoculated with the pH1N1 (1.28) or the swH1N1 virus (0.77) (P < 0.05). The highest percentage of pulmonary lesions was observed in non-colostrated/pH1N1 pigs (11.88%) at 6 days post-challenge. Cross reactivity was observed between the pH1N1 and swH1N1 viruses, as the maternal antibodies against the swH1N1 virus successfully neutralized the pH1N1 virus infection.

Isolation and characterization of porcine epidemic diarrhea virus associated with the 2014 disease outbreak in Mexico: case report.

BACKGROUND: Interest in porcine epidemic diarrhea has grown since the 2013 outbreak in the United States caused major losses, with mortality rates up to 100 % in suckling piglets. In Mexico, an outbreak of porcine epidemic diarrhea, characterized by 100 % mortality in piglets, began in March 2014 in the State of Mexico. METHODS: The aim of this study was to confirm and identify porcine epidemic diarrhea virus (PEDV) in samples from piglets with suggestive clinical signs using virological, histological, and molecular techniques. Necropsy was performed on 13 piglets from two litters with initial and advanced clinical signs. Suggestive lesions of acute infection with PEDV were detected in histological sections of the small and large bowels; specifically, multiple virus particles with visible crown-shaped projections were observed using electron microscopy and negative staining. Viral isolation was performed in Vero cells with trypsin. Infection was monitored by observation of cytopathic effect, and titration was determined by TCID50/ml. The presence of the PEDV in cultures and clinical samples was confirmed by RT-PCR amplification and sequencing of a 651-bp segment of the S glycoprotein gene, as well as a 681-bp matrix protein gene. RESULTS: The nucleotide sequence analysis of the Mexican isolates showed marked homology to viruses that circulated in 2013 in Colorado, USA. CONCLUSIONS: In this paper we confirm the isolation and characterization of PEDV from animals with early and advanced clinical signs.